1. Field of the Invention
This invention relates to food warmers, and in particular to variable-heat chafing-dish burners and methods of use.
2. Background of the Invention
It is uncertain when or how human beings first started to cook. Although prehistoric man discovered how to make fire ca. 500,000 B.C., and probably used same to heat food over small open fires, it is probable that naturally occurring fire was used for that purpose even before then.
Ancient Egyptians used mainly open fires for cooking, and also baked bread in earthen ovens, using wood and its byproduct, charcoal, as fuel. Romans used elevated brick fireplaces, over which iron kettles were suspended by tripods.
By the time the Middle Ages rolled around, most European people cooked in fireplaces, using iron kettles to heat liquids and pointed metal rods called spits to cook meat. Because many houses did not have a built-in oven, communal ovens and shared fireplaces were a common occurrence during this time period.
In the new world, North Americans cooked food using methods which were similar to those employed in Europe: fireplaces, heating kettles and meat on spits. In South America, gratings-like parillas were used to support meat (such as lamb) cooked outside over open fires. Large spits bearing cross-members supported entire animals, which were broiled whole around large bonfires called asados.
The 1800s saw the advent of iron cookstoves, the first practical exemple of which was patented in the United States in 1833. These stoves burned coal, and were more practical and convenient than wood-burning fireplaces.
The twentieth century has seen dramatic advances in cooking technology, including gas and electric stoves and ovens, microwave and convection ovens, pressure cookers, etc. One important advance has been the development of the modern chafing dish, which uses a burner to heat a water-filled pan. The heated water in turn heats a pan which contains the food itself. This form of food warming has made possible the modern hot food buffet, which features a variety of warm food maintained at temperature in a series of chafing dishes.
A major technological advance in and of itself which has made the chafing dish a reality is the chafing-dish burner. Chafing-dish burners typically use either a liquid fuel such as diethylene glycol ("DEG") or a solid fuel such as Stern.RTM..
When chafing dishes are used in hot-food buffet arrangements, the buffet is set up by filling the chafing dishes with water to the appropriate extent, positioning the chafing-dish burners under the chafing dishes, and heating the water to the correct temperature (typically in the 180.degree. F.-200.degree. F. range). At some point during the water heating process, the pans of food are placed in contact with the heated water, so as to heat, and maintain heated, the food which is in them.
The most time-consuming event in the whole process is heating the water. This step generally takes one to two hours. In the case of caterers setting up a buffet at a field location, this means the caterers must appear on location an hour or two before starting to serve food, merely to heat water! Thus, a major disadvantage with currently available fixed-heat chafing-dish burners is the long time period required to heat the chafing-dish water, along with the associated cost of tying up personnel to accomplish this task.